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Xu Z, Li Y, Liu Y, Liu S, Zhang L, Wang J, Su S, Liu L, Meng L, Zhu H, Sun J, Shao L, Li L, Zhai Y, Li G, Cao Z. Diverse associations observed between pregnancy complications and RBC or plasma folates determined by an in-house developed LC-MS/MS method. Ann Med 2023; 55:2265381. [PMID: 37824254 PMCID: PMC10572033 DOI: 10.1080/07853890.2023.2265381] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/27/2023] [Accepted: 09/26/2023] [Indexed: 10/14/2023] Open
Abstract
BACKGROUND As folates are essential for embryonic development and growth, it is necessary to accurately determine the levels of folates in plasma and red blood cells (RBCs) for clinical intervention. The aims of this study were to develop and validate a liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for quantitation of folates in plasma and RBCs and to examine the association between plasma and RBC folate concentrations and gestational diabetes mellitus (GDM), gestational hypertension (GH) and preeclampsia (PE). METHODS With the in-house developed LC-MS/MS, a retrospective cross-sectional study was conducted. The healthy pregnant women of first- (n = 147), second- (n = 84) and third-trimester (n = 141) or the women diagnosed with GDM (n = 84), GH (n = 58) or PE (n = 23), that were aged between 22 and 46 years old and registered at our institute, were subjected for measurement of folic acid (FA) and 5-methyltetrahydrofolate (5-MTHF), followed by appropriate statistical association analysis. RESULTS The assay for simultaneous quantitation of FA and 5-MTHF in plasma and RBCs was linear, stable, with imprecision less than 15% and recoveries within ±10%. The lower limits of quantification for FA and 5-MTHF measurement in whole blood were 0.57 and 1.09 nmol/L, and in plasma were 0.5 and 1 nmol/L, respectively. In the association analysis, the patients with lower RBC folate level (<906 nmol/L) presented higher risks of PE development (OR 4.861 [95% CI 1.411-16.505]) by logistic regression and restricted cubic spline (RCS) regression in a nonlinear fashion. In addition, higher level of plasma folates in pregnancy was significantly associated with GH risk but may be protective for the development of GDM. CONCLUSIONS The in-house developed LC-MS/MS method for folates and metabolites in plasma or RBC showed satisfactory analytical performance for clinical application. Further, the levels of folates and metabolites were diversely associated with GDM, GH and PE development.
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Affiliation(s)
- Zhengwen Xu
- Department of Laboratory Medicine, Beijing Obstetrics and Gynecology Hospital, Capital Medical University, Beijing Maternal and Child Health Care Hospital, Beijing, PR China
- Center of Clinical Mass Spectrometry, Beijing Obstetrics and Gynecology Hospital, Capital Medical University, Beijing Maternal and Child Health Care Hospital, Beijing, PR China
| | - Youran Li
- Department of Laboratory Medicine, Beijing Obstetrics and Gynecology Hospital, Capital Medical University, Beijing Maternal and Child Health Care Hospital, Beijing, PR China
- Center of Clinical Mass Spectrometry, Beijing Obstetrics and Gynecology Hospital, Capital Medical University, Beijing Maternal and Child Health Care Hospital, Beijing, PR China
| | - Ying Liu
- Department of Laboratory Medicine, Beijing Obstetrics and Gynecology Hospital, Capital Medical University, Beijing Maternal and Child Health Care Hospital, Beijing, PR China
- Center of Clinical Mass Spectrometry, Beijing Obstetrics and Gynecology Hospital, Capital Medical University, Beijing Maternal and Child Health Care Hospital, Beijing, PR China
| | | | - Lin Zhang
- Department of Internal Medicine, Beijing Obstetrics and Gynecology Hospital, Capital Medical University, Beijing Maternal and Child Health Care Hospital, Beijing, PR China
| | - Jing Wang
- Department of Internal Medicine, Beijing Obstetrics and Gynecology Hospital, Capital Medical University, Beijing Maternal and Child Health Care Hospital, Beijing, PR China
| | - Shaofei Su
- Central Laboratory, Beijing Obstetrics and Gynecology Hospital, Capital Medical University, Beijing Maternal and Child Health Care Hospital, Beijing, PR China
| | - Lin Liu
- Department of Laboratory Medicine, Beijing Obstetrics and Gynecology Hospital, Capital Medical University, Beijing Maternal and Child Health Care Hospital, Beijing, PR China
- Center of Clinical Mass Spectrometry, Beijing Obstetrics and Gynecology Hospital, Capital Medical University, Beijing Maternal and Child Health Care Hospital, Beijing, PR China
| | - Lanlan Meng
- Department of Laboratory Medicine, Beijing Obstetrics and Gynecology Hospital, Capital Medical University, Beijing Maternal and Child Health Care Hospital, Beijing, PR China
- Center of Clinical Mass Spectrometry, Beijing Obstetrics and Gynecology Hospital, Capital Medical University, Beijing Maternal and Child Health Care Hospital, Beijing, PR China
| | - Hongyuan Zhu
- Department of Laboratory Medicine, Beijing Obstetrics and Gynecology Hospital, Capital Medical University, Beijing Maternal and Child Health Care Hospital, Beijing, PR China
- Center of Clinical Mass Spectrometry, Beijing Obstetrics and Gynecology Hospital, Capital Medical University, Beijing Maternal and Child Health Care Hospital, Beijing, PR China
| | - Jingru Sun
- Health Biotech Co. Ltd, Beijing, PR China
| | - Lijun Shao
- Health Biotech Co. Ltd, Beijing, PR China
| | - Lin Li
- Health Biotech Co. Ltd, Beijing, PR China
| | - Yanhong Zhai
- Department of Laboratory Medicine, Beijing Obstetrics and Gynecology Hospital, Capital Medical University, Beijing Maternal and Child Health Care Hospital, Beijing, PR China
- Center of Clinical Mass Spectrometry, Beijing Obstetrics and Gynecology Hospital, Capital Medical University, Beijing Maternal and Child Health Care Hospital, Beijing, PR China
| | - Guanghui Li
- Department of Obstetrics, Beijing Obstetrics and Gynecology Hospital, Division of Endocrinology and Metabolism, Capital Medical University, Beijing Maternal and Child Health Care Hospital, Beijing, PR China
| | - Zheng Cao
- Department of Laboratory Medicine, Beijing Obstetrics and Gynecology Hospital, Capital Medical University, Beijing Maternal and Child Health Care Hospital, Beijing, PR China
- Center of Clinical Mass Spectrometry, Beijing Obstetrics and Gynecology Hospital, Capital Medical University, Beijing Maternal and Child Health Care Hospital, Beijing, PR China
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Ji Y, Luo H, Li H, Lin Z, Luo W. Determination of plasma homocysteine with a UHPLC-MS/MS method: Application to analyze the correlation between plasma homocysteine and whole blood 5-methyltetrahydrofolate in healthy volunteers. Biomed Chromatogr 2020; 34:e4845. [PMID: 32267542 DOI: 10.1002/bmc.4845] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2020] [Revised: 03/27/2020] [Accepted: 04/04/2020] [Indexed: 02/05/2023]
Abstract
An ultra-high performance liquid chromatography tandem mass spectrometry method was developed for determination of homocysteine (HCY) in human plasma. The HCY was derivatized with 2-chloro-1-methylquinolinium tetrafluoroborate and isolated using solid-phase extraction. Derivatization, isolation and detection procedures were optimized. Satisfactory linearity was obtained with determination coefficients (r2 ) >0.999. The intra- and inter-day precisions were in the interval of 1.2-5.1% and accuracy was within ±7%. Mean recoveries were close to 100%. The limit of detection and the limit of quantification were 0.46 and 1.38 μmol/L, respectively. The method was then applied to investigate the relationship between plasma HCY and whole blood 5-methyltetrahydrofolate levels in healthy volunteers. The results revealed that the plasma level of HCY was significantly negatively correlated to whole blood 5-methyltetrahydrofolate in volunteers.
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Affiliation(s)
- Yubin Ji
- Bio-analytical Laboratory, Shantou University Medical College, Shantou, China
| | - Hongjun Luo
- Bio-analytical Laboratory, Shantou University Medical College, Shantou, China
| | - Hui Li
- Bio-analytical Laboratory, Shantou University Medical College, Shantou, China
| | - Zhexuan Lin
- Bio-analytical Laboratory, Shantou University Medical College, Shantou, China
| | - Wenhong Luo
- Bio-analytical Laboratory, Shantou University Medical College, Shantou, China
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3
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Shohag MJI, Yang Q, Wei Y, Zhang J, Khan FZ, Rychlik M, He Z, Yang X. A rapid method for sensitive profiling of folates from plant leaf by ultra-performance liquid chromatography coupled to tandem quadrupole mass spectrometer. J Chromatogr B Analyt Technol Biomed Life Sci 2016; 1040:169-179. [PMID: 27987487 DOI: 10.1016/j.jchromb.2016.11.033] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2015] [Revised: 11/12/2016] [Accepted: 11/22/2016] [Indexed: 11/18/2022]
Abstract
Previous published methods for the analysis of folates are time consuming because of lengthy sample extraction, clean-up and total running time. This study details the development and validation of a rapid, sensitive and robust method that combines a simple extraction step with ultra-performance liquid chromatography coupled to tandem quadrupole mass spectrometry. Here, we reported application of a tandem quadrupole mass spectrometer to analyze maximum seven vitamers of folate from plant origin. The analytical performance was evaluated by linearity, sensitivity, precision, recovery test and analysis of certified reference materials. The limit of detection and limit of quantification ranged between 0.003 and 0.021μg/100g FW and between 0.011 and 0.041μg/100g FW, respectively; the recovery and precession ranged from 71.27 to 99. 01% and from 1.7 to 7.8% RSD, respectively, depending upon folate vitamers. This newly developed and validated method is rapid (a chromatographic run time of 5min), easy to be performed (no laborious and time consuming clean-up) and can be used to simultaneously analyze seven vitamers of folate from plant sources.
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Affiliation(s)
- M J I Shohag
- Ministry of Education Key Laboratory of Environmental Remediation and Ecosystem Health, College of Environmental and Resources Science, Zhejiang University, Hangzhou, 310058, People's Republic of China; Department of Agriculture, Bangabandhu Sheikh Mujibur Rahman Science and Technology University, Gopalganj, 8100, Bangladesh
| | - Qianying Yang
- Ministry of Education Key Laboratory of Environmental Remediation and Ecosystem Health, College of Environmental and Resources Science, Zhejiang University, Hangzhou, 310058, People's Republic of China
| | - Yanyan Wei
- Ministry of Education Key Laboratory of Environmental Remediation and Ecosystem Health, College of Environmental and Resources Science, Zhejiang University, Hangzhou, 310058, People's Republic of China; College of Agriculture, Guangxi University, Nanning 530000, People's Republic of China
| | - Jie Zhang
- Ministry of Education Key Laboratory of Environmental Remediation and Ecosystem Health, College of Environmental and Resources Science, Zhejiang University, Hangzhou, 310058, People's Republic of China
| | - Farhana Zerin Khan
- Ministry of Education Key Laboratory of Environmental Remediation and Ecosystem Health, College of Environmental and Resources Science, Zhejiang University, Hangzhou, 310058, People's Republic of China
| | - Michael Rychlik
- Chair of Analytical Food Chemistry, Technische Universität München, Alte Akademie 10, D-85350 Freising, Germany
| | - Zhenli He
- Indian River Research and Education Center, Institute of Food and Agricultural Sciences, University of Florida, Fort Pierce, FL 34945, United States
| | - Xiaoe Yang
- Ministry of Education Key Laboratory of Environmental Remediation and Ecosystem Health, College of Environmental and Resources Science, Zhejiang University, Hangzhou, 310058, People's Republic of China.
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Bertazzo S, Maidment SCR, Kallepitis C, Fearn S, Stevens MM, Xie HN. Fibres and cellular structures preserved in 75-million-year-old dinosaur specimens. Nat Commun 2015; 6:7352. [PMID: 26056764 PMCID: PMC4468865 DOI: 10.1038/ncomms8352] [Citation(s) in RCA: 59] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2015] [Accepted: 04/30/2015] [Indexed: 02/05/2023] Open
Abstract
Exceptionally preserved organic remains are known throughout the vertebrate fossil record, and recently, evidence has emerged that such soft tissue might contain original components. We examined samples from eight Cretaceous dinosaur bones using nano-analytical techniques; the bones are not exceptionally preserved and show no external indication of soft tissue. In one sample, we observe structures consistent with endogenous collagen fibre remains displaying ∼ 67 nm banding, indicating the possible preservation of the original quaternary structure. Using ToF-SIMS, we identify amino-acid fragments typical of collagen fibrils. Furthermore, we observe structures consistent with putative erythrocyte remains that exhibit mass spectra similar to emu whole blood. Using advanced material characterization approaches, we find that these putative biological structures can be well preserved over geological timescales, and their preservation is more common than previously thought. The preservation of protein over geological timescales offers the opportunity to investigate relationships, physiology and behaviour of long extinct animals.
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Affiliation(s)
- Sergio Bertazzo
- Department of Materials, Imperial College London, South Kensington Campus, London SW7 2AZ, UK
- Present address: Department of Medical Physics and Biomedical Engineering, University College London, Malet Place Engineering Building, London WC1E 6BT, UK
| | - Susannah C. R. Maidment
- Department of Earth Science and Engineering, Imperial College London, South Kensington Campus, London SW7 2AZ, UK
| | - Charalambos Kallepitis
- Department of Materials, Imperial College London, South Kensington Campus, London SW7 2AZ, UK
- Department of Bioengineering, Imperial College London, South Kensington Campus, London SW7 2AZ, UK
- Institute for Biomedical Engineering, Imperial College London, South Kensington Campus, London SW7 2AZ, UK
| | - Sarah Fearn
- Department of Materials, Imperial College London, South Kensington Campus, London SW7 2AZ, UK
| | - Molly M. Stevens
- Department of Materials, Imperial College London, South Kensington Campus, London SW7 2AZ, UK
- Department of Bioengineering, Imperial College London, South Kensington Campus, London SW7 2AZ, UK
- Institute for Biomedical Engineering, Imperial College London, South Kensington Campus, London SW7 2AZ, UK
| | - Hai-nan Xie
- Department of Materials, Imperial College London, South Kensington Campus, London SW7 2AZ, UK
- Department of Bioengineering, Imperial College London, South Kensington Campus, London SW7 2AZ, UK
- Institute for Biomedical Engineering, Imperial College London, South Kensington Campus, London SW7 2AZ, UK
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5
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Tyagi K, Upadhyaya P, Sarma S, Tamboli V, Sreelakshmi Y, Sharma R. High performance liquid chromatography coupled to mass spectrometry for profiling and quantitative analysis of folate monoglutamates in tomato. Food Chem 2015; 179:76-84. [PMID: 25722141 DOI: 10.1016/j.foodchem.2015.01.110] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2014] [Revised: 01/20/2015] [Accepted: 01/23/2015] [Indexed: 10/24/2022]
Abstract
Folates are essential micronutrients for animals as they play a major role in one carbon metabolism. Animals are unable to synthesize folates and obtain them from plant derived food. In the present study, a high performance liquid chromatography coupled to mass spectrometric (HPLC-MS/MS) method was developed for the high throughput screening and quantitative analysis of folate monoglutamates in tomato fruits. For folate extraction, several parameters were optimized including extraction conditions, pH range, amount of tri-enzyme and boiling time. After processing the extract was purified using ultra-filtration with 10 kDa membrane filter. The ultra-filtered extract was chromatographed on a RP Luna C18 column using gradient elution program. The method was validated by determining linearity, sensitivity and recovery. This method was successfully applied to folate estimation in spinach, capsicum, and garden pea and demonstrated that this method offers a versatile approach for accurate and fast determination of different folate monoglutamates in vegetables.
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Affiliation(s)
- Kamal Tyagi
- Repository of Tomato Genomics Resources, Department of Plant Sciences, School of Life Sciences, University of Hyderabad, Hyderabad 500046, India.
| | - Pallawi Upadhyaya
- Repository of Tomato Genomics Resources, Department of Plant Sciences, School of Life Sciences, University of Hyderabad, Hyderabad 500046, India.
| | - Supriya Sarma
- Repository of Tomato Genomics Resources, Department of Plant Sciences, School of Life Sciences, University of Hyderabad, Hyderabad 500046, India.
| | - Vajir Tamboli
- Repository of Tomato Genomics Resources, Department of Plant Sciences, School of Life Sciences, University of Hyderabad, Hyderabad 500046, India.
| | - Yellamaraju Sreelakshmi
- Repository of Tomato Genomics Resources, Department of Plant Sciences, School of Life Sciences, University of Hyderabad, Hyderabad 500046, India.
| | - Rameshwar Sharma
- Repository of Tomato Genomics Resources, Department of Plant Sciences, School of Life Sciences, University of Hyderabad, Hyderabad 500046, India.
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6
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De Brouwer V, Storozhenko S, Van De Steene JC, Wille SM, Stove CP, Van Der Straeten D, Lambert WE. Optimisation and validation of a liquid chromatography–tandem mass spectrometry method for folates in rice. J Chromatogr A 2008; 1215:125-32. [DOI: 10.1016/j.chroma.2008.11.004] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2008] [Revised: 10/22/2008] [Accepted: 11/03/2008] [Indexed: 10/21/2022]
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7
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Green R. Indicators for assessing folate and vitamin B12 status and for monitoring the efficacy of intervention strategies. Food Nutr Bull 2008; 29:S52-63; discussion S64-6. [PMID: 18709881 DOI: 10.1177/15648265080292s108] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Deficiencies of folate or of vitamin B12 are widespread and constitute a major global burden of morbidity affecting all age groups. Detecting or confirming the presence of folate or vitamin B12 deficiency and distinguishing one from the other depends, ultimately, on laboratory testing. Tests to determine the presence of folate or vitamin B12 deficiency are used singly or in combination to establish the nutritional status and prevalence of deficiencies of the vitamins in various populations. The efficacy of interventions through the use of fortification or supplements is monitored using the same laboratory tests. Tests currently in use have limitations that can be either technical or have a biological basis. Consequently, each single test cannot attain perfect sensitivity, specificity, or predictive value. Laboratory indicators of vitamin B12 or folate status involve measurement of either the total or a physiologically relevant fraction of the vitamin in a compartment such as the blood. Thus, assays to measure vitamin B12 or folate in plasma or serum as well as folate in red blood cells are in widespread use, and more recently, methods to measure vitamin B12 associated with the plasma binding protein transcobalamin (holotranscobalamin) have been developed. Alternatively, levels of surrogate biochemical markers that reflect the metabolic function of the vitamin can be used. Surrogates most commonly used are plasma homocysteine, for detection of either vitamin B12 or folate deficiency and methylmalonic acid for detection of vitamin B12 deficiency. The general methods as well as their uses, indications, and limitations are presented.
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Affiliation(s)
- Ralph Green
- Department of Medical Pathology and Laboratory Medicine, University of California, Davis, California, USA
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8
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Hannisdal R, Svardal A, Ueland PM. Measurement of Folate in Fresh and Archival Serum Samples as p-Aminobenzoylglutamate Equivalents. Clin Chem 2008; 54:665-72. [DOI: 10.1373/clinchem.2007.100511] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Abstract
Background: The development of accurate and precise folate assays has been difficult, mainly because of folate instability. Large interassay and interlaboratory differences have been reported. We therefore developed a serum folate assay that measures folate and putative degradation products as p-aminobenzoylglutamate (pABG) equivalents following oxidation and acid hydrolysis.
Methods: Serum was deproteinized with acid in the presence of 2 internal calibrators ([13C2]pABG and [13C5]5-methyltetrahydrofolate). 5-Methyltetrahydrofolate and other folate species in serum were converted to pABG by oxidation and mild acid hydrolysis. pABG and its internal calibrators were quantified by liquid chromatography–tandem mass spectrometry (LC-MS/MS).
Results: The limit of quantification was 0.25 nmol/L, and the assay was linear in the range 0.25–96 nmol/L, which includes the 99.75 percentile for serum folate concentrations in healthy blood donors. Within- and between-day imprecision was ≤5%. We detected no residual folate in serum samples after sample preparation. Folate concentrations in fresh serum samples obtained with the pABG assay and with a microbiologic assay showed good agreement (r = 0.96). In stored samples containing low folate concentrations due to folate degradation, the pABG assay yielded substantially higher folate concentrations than the microbiologic assay.
Conclusions: The pABG assay combines automated sample preparation with LC-MS/MS analysis. It allows measurement of folate not only in fresh samples of serum/plasma but also in stored samples in which the folate has become oxidized and degraded to an extent that it cannot be assayed with traditional folate assays.
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Affiliation(s)
- Rita Hannisdal
- LOCUS for Homocysteine and Related Vitamins and
- Section for Pharmacology, Institute of Medicine, University of Bergen
| | - Asbjørn Svardal
- LOCUS for Homocysteine and Related Vitamins and
- Section for Pharmacology, Institute of Medicine, University of Bergen
| | - Per Magne Ueland
- LOCUS for Homocysteine and Related Vitamins and
- Section for Pharmacology, Institute of Medicine, University of Bergen
- Haukeland University Hospital, Bergen, Norway
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Li XY, Zhang QL, Lian HZ, Xu JJ, Chen HY. Separation of three water-soluble vitamins by poly(dimethylsiloxane) microchannel electrophoresis with electrochemical detection. J Sep Sci 2007; 30:2320-5. [PMID: 17668908 DOI: 10.1002/jssc.200700155] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
A method for rapid separation and sensitive determination of three water-soluble vitamins, pyridoxine, ascorbic acid (VC), and p-aminobenzoic acid (PABA) has been developed by PDMS microchannel electrophoresis integrated with amperometric detection. After treatment of the microchip with oxygen plasma, the peak shapes of the three analytes were essentially improved. Pyridoxine, VC, and PABA were well separated within only 80 s in a running buffer of 20 mM borate solution (pH 8.5). Good linearity was obtained within the concentration range of 2-200 microM for the three water-soluble vitamins. The detection limits were 1.0 microM for pyridoxine and VC, and 1.5 microM for PABA. The proposed method has been successfully applied to real human urine sample, without solid phase extraction, with recoveries of 80-122% for the three water-soluble vitamins.
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Affiliation(s)
- Xiang-Yun Li
- Key Lab of Analytical Chemistry for Life Science, Ministry of Education, School of Chemistry & Chemical Engineering, Nanjing University, Nanjing, China
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Dhananjeyan MR, Bykowski C, Trendel JA, Sarver JG, Ando H, Erhardt PW. Simultaneous determination of procaine and para-aminobenzoic acid by LC-MS/MS method. J Chromatogr B Analyt Technol Biomed Life Sci 2006; 847:224-30. [PMID: 17070118 DOI: 10.1016/j.jchromb.2006.10.004] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2006] [Revised: 10/03/2006] [Accepted: 10/08/2006] [Indexed: 11/16/2022]
Abstract
A sensitive high performance liquid chromatography tandem mass spectrometry (LC-MS/MS) method has been developed for simultaneous determination of procaine and its metabolite p-aminobenzoic acid (PABA). N-Acetylprocainamide (NAPA) was used as an internal standard for procaine and PABA analysis. This assay method has also been validated in terms of linearity, lower limit of detection, lower limit of quantitation, accuracy and precision as per ICH guidelines. Chromatography was carried out on an XTerra MS C(18) column and mass spectrometric analysis was performed using a Quattro Micro mass spectrometer working with electro-spray ionization (ESI) source in the positive ion mode. Enhanced selectivity was achieved using multiple reaction monitoring (MRM) functions, m/z 237-->100, m/z 138-->120, and m/z 278-->205 for procaine, PABA and NAPA, respectively. Retention times for PABA, procaine and NAPA were 4.0, 4.7 and 5.8min, respectively. Linearity for each calibration curve was observed across a range from 100nM to 5000nM for PABA, and from 10nM to 5000nM for procaine. The intra- and inter-day relative standard deviations (RSD) were <5%.
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11
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Fazili Z, Pfeiffer CM, Zhang M, Jain R. Erythrocyte folate extraction and quantitative determination by liquid chromatography-tandem mass spectrometry: comparison of results with microbiologic assay. Clin Chem 2005; 51:2318-25. [PMID: 16214826 DOI: 10.1373/clinchem.2005.053801] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
BACKGROUND Erythrocyte folate analysis is an important diagnostic tool to establish folate status or screen for folate deficiency. METHODS We evaluated conditions that influence the complete hemolysis and deconjugation of folate polyglutamates to folate monoglutamates (FMGs) from whole blood (WB). WB samples were hemolyzed in 10 g/L ascorbic acid at various temperatures (room temperature, 30 degrees C, and 37 degrees C; n = 15) or hemolysate pH values (pH 4.0, 4.7, 5.2; n = 11) and incubated up to 6 h. FMGs and folate diglutamates (FDGs) were analyzed by liquid chromatography-tandem mass spectrometry (LC/MS/MS) and total folate (TF) by microbiologic assay. We investigated delaying hemolysis by freezing WB for 10 days (n = 20). RESULTS Hemolysates frozen immediately after preparation contained 22%-27% FDGs, depending on hemolysate pH. The proportion of FDGs decreased to <3% after incubation at pH 4.7/37 degrees C for 3 h and did not significantly change on extended incubation up to 5 h. Short-term delayed hemolysis of WB produced results indistinguishable from those of immediate hemolysis. TF results obtained by the microbiologic assay were not different across incubation conditions and agreed with the sum of FMGs and FDGs by LC/MS/MS. The difference between the 2 methods was an insignificant 3% for pH 4.7/37 degrees C for 3 h. CONCLUSIONS Hemolysate incubation up to 2 h at 37 degrees C is not adequate for full polyglutamate deconjugation. We obtained the highest yield of FMGs with lowest FDG concentrations at pH 4.7/37 degrees C for 3 h. Delaying hemolysis of WB for several days had no negative effect on measurable folate for presumed MTHFR C/C genotype samples.
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Affiliation(s)
- Zia Fazili
- Inorganic Toxicology and Nutrition Branch, Division of Laboratory Sciences, National Center for Environmental Health, Centers for Disease Control and Prevention, Atlanta, GA 30341, USA
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12
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Quinlivan EP, Hanson AD, Gregory JF. The analysis of folate and its metabolic precursors in biological samples. Anal Biochem 2005; 348:163-84. [PMID: 16266679 DOI: 10.1016/j.ab.2005.09.017] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2005] [Revised: 09/09/2005] [Accepted: 09/13/2005] [Indexed: 10/25/2022]
Affiliation(s)
- Eoin P Quinlivan
- Department of Food Science and Human Nutrition, University of Florida, Gainesville, FL 32611, USA
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13
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Owens JE, Holstege DM, Clifford AJ. Quantitation of total folate in whole blood using LC-MS/MS. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2005; 53:7390-4. [PMID: 16159163 DOI: 10.1021/jf0510485] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
An accurate method for measuring whole blood total folate using liquid chromatography with tandem mass spectrometry is described and compared to GC/MS and a chemiluminescence assay. Whole blood from normal adults (n = 15) was fortified with a [(13)C(6)]para-aminobenzoic acid (pABA) internal standard and treated with 12.1 N hydrochloric acid at 110 degrees C for 4 h to hydrolyze all folates to pABA. Contaminants in the hydrolysate were adsorbed onto a C18 SPE cartridge. The eluate containing the folate catabolite pABA was partitioned into ethyl acetate and methylesterified with trimethylsilyldiazomethane. The methyl-pABA derivatives were quantified by positive-ion atmospheric pressure chemical ionization (APCI)LC-MS/MS. An isocratic mobile phase of acetonitrile-water (70:30) (v/v) on a C18 analytical column was used with a postcolumn reagent of 0.025% formic acid. The limit of quantitation for folate was 56.6 nmol/L RBC, and the limit of detection was 22.6 nmol/L RBC. Folate levels as determined by LC-MS/MS correlated well with the chemiluminescence assay and a GC/MS method. This new LC-MS/MS method provides enhanced sample throughput (n = 36 per day) as compared to GC/MS methods. LC-MS/MS will enable accurate measurements of red blood cell (RBC) folate in nutrition surveys and clinical trials.
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Affiliation(s)
- Janel E Owens
- Department of Nutrition and Division of Agricultural and Natural Resources Analytical Laboratory, University of California, Davis, 95616, USA
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Traditional and accelerator mass spectrometry for quantitation of human folate pools. Trends Food Sci Technol 2005. [DOI: 10.1016/j.tifs.2005.03.006] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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15
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Storozhenko S, Ravanel S, Zhang GF, Rébeillé F, Lambert W, Van Der Straeten D. Folate enhancement in staple crops by metabolic engineering. Trends Food Sci Technol 2005. [DOI: 10.1016/j.tifs.2005.03.007] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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16
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Clifford AJ, Noceti EM, Block-Joy A, Block T, Block G. Erythrocyte folate and its response to folic acid supplementation is assay dependent in women. J Nutr 2005; 135:137-43. [PMID: 15623845 DOI: 10.1093/jn/135.1.137] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Optimizing folate status requires continued monitoring of erythrocyte (RBC) folate and folate intake. The accuracy of RBC folate assays remains a concern. Therefore, we measured RBC folate with 4 different assays, examined the interassay correlations, and compared RBC folate with folate intake as measured by an abbreviated folate-targeted food/supplement screener. The screener had 21 questions (19 diet, 2 supplement) and measured usual and customary intakes of dietary folate equivalents (DFEs). Our design was a 4 x 2 x 2 factorial, 4 assays in pregnant and nonpregnant women before and after each group received a folic acid supplement (1814 nmol/d) for 30-60 d. Folate assays included L. casei, chemiluminescence, GC-MS, and radioassay (RA). Baseline RBC folate levels ranked low to high by assay (mean +/- SE) were as follows: 1155 +/- 44 nmol/L (L. casei) < 1390 +/- 43 nmol/L (chemiluminescence) < 1531 +/- 39 nmol/L (GC-MS) < 1727 +/- 55 nmol/L (RA) (P < 0.0001). Supplementation raised RBC folate levels (mean +/- SE) as follows: 138 +/- 63 nmol/L (chemiluminescence) < 267 +/- 64 nmol/L (GC-MS) = 285 +/- 75 nmol/L (L. casei) < 351 +/- 87 nmol/L (RA). Pregnant women had higher RBC folate than nonpregnant women using chemiluminescence and RA. Interassay correlations (r) ranged from 0.4679 to 0.8261 (P < 0.001). Correlations of RBC folate with folate intake ranged from 0.2676 to 0.4622 (P < 0.0004). We conclude that RBC folate levels are assay dependent, as is the definition of optimized status; there continues to be a need for an accurate assay of RBC folate. RBC folate correlated with total folate intake using a folate-targeted food/supplement screener.
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Affiliation(s)
- Andrew J Clifford
- Department of Nutrition, University of California, Davis, CA 95616, USA.
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Zhang GF, Mortier KA, Storozhenko S, Van De Steene J, Van Der Straeten D, Lambert WE. Free and total para-aminobenzoic acid analysis in plants with high-performance liquid chromatography/tandem mass spectrometry. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2005; 19:963-9. [PMID: 15759312 DOI: 10.1002/rcm.1878] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
para-Aminobenzoic acid (PABA), a precursor in the synthesis of folates in plants, is determined by liquid chromatography/tandem mass spectrometry (LC/MS/MS). In plants PABA can be converted into its beta-D-glucopyranosyl ester (PABA-Glc) and can also exist in its free form. In this work, we developed and validated a quantitative method to study free and total PABA in plants. The total PABA (free PABA plus PABA-Glc) can be evaluated after acid hydrolysis at 80 degrees C for 2 hours. The plant material is homogenized and the PABA content is quantified using the standard addition procedure. The validated method is selective, sensitive, simple, accurate, has a recovery between 99.6 to 102.5%, is reproducible (RSD between 1.4 and 4.4%), and is linear between 2.5 and 1538 ng/mL. Free and total PABA determinations in five vegetables showed that different plant species had different amounts of free and total PABA, and that the ratios of total versus free PABA were also variable. This new method could be valuable for studies of folate synthesis in plants.
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Affiliation(s)
- Guo-Fang Zhang
- Laboratory of Toxicology, Ghent University, Harelbekestraat 72, B-9000 Ghent, Belgium
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Fazili Z, Pfeiffer CM. Measurement of folates in serum and conventionally prepared whole blood lysates: application of an automated 96-well plate isotope-dilution tandem mass spectrometry method. Clin Chem 2004; 50:2378-81. [PMID: 15459090 DOI: 10.1373/clinchem.2004.036541] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Zia Fazili
- Division of Laboratory Sciences, National Center for Environmental Health, Centers for Disease Control and Prevention, Atlanta, GA 30341, USA
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Lin Y, Dueker SR, Follett JR, Fadel JG, Arjomand A, Schneider PD, Miller JW, Green R, Buchholz BA, Vogel JS, Phair RD, Clifford AJ. Quantitation of in vivo human folate metabolism. Am J Clin Nutr 2004; 80:680-91. [PMID: 15321809 DOI: 10.1093/ajcn/80.3.680] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND A quantitative understanding of human folate metabolism is needed. OBJECTIVE The objective was to quantify and interpret human folate metabolism as it might occur in vivo. DESIGN Adults (n = 13) received 0.5 nmol [(14)C]pteroylmonoglutamate (100 nCi radioactivity) plus 79.5 nmol pteroylmonoglutamate in water orally. (14)C was measured in plasma, erythrocytes, urine, and feces for >/=40 d. Kinetic modeling was used to analyze and interpret the data. RESULTS According to the data, the population was healthy and had a mean dietary folate intake of 1046 nmol/d, and the apparent dose absorption of (14)C was 79%. The model predictions showed that only 0.25% of plasma folate was destined for marrow, mean bile folate flux was 5351 nmol/d, and the digestibility of the mix (1046 + 5351 nmol/d) was 92%. About 33% of visceral pteroylmonoglutamate was converted to the polyglutamate form, most of the body folate was visceral (>99%), most of the visceral folate was pteroylpolyglutamate (>98%), total body folate was 225 micromol, and pteroylpolyglutamate synthesis, recycling, and catabolism were 1985, 1429, and 556 nmol/d, respectively. Mean residence times were 0.525 d as visceral pteroylmonoglutamate, 119 d as visceral pteroylpolyglutamate, 0.0086 d as plasma folate, and 0.1 d as gastrointestinal folate. CONCLUSIONS Across subjects, folate absorption, bile folate flux, and body folate stores were larger than prior estimates. Marrow folate uptake and pteroylpolyglutamate synthesis, recycling, and catabolism are saturable processes. Visceral pteroylpolyglutamate was an immediate precursor of plasma p-aminobenzoylglutamate. The model is a working hypothesis with derived features that are explicitly model-dependent. It successfully quantitated folate metabolism, encouraging further rigorous testing.
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Affiliation(s)
- Yumei Lin
- Departments of Nutrition and Pathology Department, University of California-Davis, One Shields Avenue,. Davis. CA 95616-8669, USA
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Zhang GF, Maudens KE, Storozhenko S, Mortier KA, Van Der Straeten D, Lambert WE. Determination of total folate in plant material by chemical conversion into para-aminobenzoic acid followed by high performance liquid chromatography combined with on-line postcolumn derivatization and fluorescence detection. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2003; 51:7872-7878. [PMID: 14690367 DOI: 10.1021/jf034808p] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
A procedure involving chemical conversion of all forms of folate present in plant material into para-aminobenzoic acid (PABA) and a liquid chromatographic-fluorimetric determination with on-line postcolumn derivatization is reported. All folates are cleaved with liberation of PABA by hydrogen peroxide followed by acid hydrolysis using concentrated hydrochloric acid (37%) at 110 degrees C for 6 h. The reaction yield for individual folates conversion to PABA ranged from 44.4 to 97.3%. PABA could be determined sensitively by on-line postcolumn derivatization with fluorescamine, the detection limit for PABA being 3.02 nM. On the basis of this principle, a method for the determination of total folate in plant material, including a purification step on an affinity column, is presented, which offers a sufficient sensitivity and selectivity for routine analysis of total folate in natural samples. The total folate contents of tomatoes, carrots, white cabbage, and spinach were determined, and the results were quite comparable to the data reported. The recovery of PABA and the comparison of total folate analysis in spinach on different occasions (over 6 months) are also reported. The method is reliable, universal for all folates, including polyglutamate and monoglutamate forms, and eliminates the need for a deconjugation step and multiple conversion reactions.
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Affiliation(s)
- Guo-Fang Zhang
- Laboratory of Toxicology, Ghent University, Harelbekestraat 72, B-9000 Ghent, Belgium
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Lin Y, Dueker SR, Clifford AJ. Human whole blood folate analysis using a selected ion monitoring gas chromatography with mass selective detection protocol. Anal Biochem 2003; 312:255-7. [PMID: 12531214 DOI: 10.1016/s0003-2697(02)00502-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Affiliation(s)
- Yumei Lin
- Department of Nutrition, University of California, Davis 95616-8669, USA
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Lin Y, Dueker SR, Jones AD, Clifford AJ. A parallel processing solid phase extraction protocol for the determination of whole blood folate. Anal Biochem 2002; 301:14-20. [PMID: 11811962 DOI: 10.1006/abio.2001.5477] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We describe an improved whole blood folate analysis method that facilitates increased throughput compared to our previous method (Dueker et al. (2000) Anal. Biochem. 283, 266). Improvements include three items: first, a buffered solvent exchange to remove interfering amino acids, especially phenylalanine whose esters may interfere with the analysis because their retention times on the gas chromatography are close to those of the para-aminobenzoic acid (pABA) isotopomers; second, substituting an NH2 solid phase extraction step for an HPLC step permits the batch parallel processing of samples; third, replacing trifluoroacetyl derivatives of ethyl-esterified pABA isotopomers with heptafluorobutyl derivatives, which are better resolved on the GC column. The method measures pABA, a stable degradation product of folate. This simplifies sample handling and purification. Relative standard deviations are typically 5% or less and a single operator can process samples in batches of 40. Results from our GCMS method correlate (R = 0.98) with the Lactobacillus casei assay for whole blood folate. The modifications will facilitate the development of high throughput methods for whole blood folate. Our method holds promise for epidemiological and clinical studies, where accurate whole blood folate concentrations are needed. Because it is internally standardized, interlaboratory variation should be minimal.
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Affiliation(s)
- Yumei Lin
- Department of Nutrition, University of California, Davis, California 95616, USA
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Nelson BC, Dalluge JJ, Margolis SA. Preliminary application of liquid chromatography-electrospray-ionization mass spectrometry to the detection of 5-methyltetrahydrofolic acid monoglutamate in human plasma. JOURNAL OF CHROMATOGRAPHY. B, BIOMEDICAL SCIENCES AND APPLICATIONS 2001; 765:141-50. [PMID: 11767307 DOI: 10.1016/s0378-4347(01)00412-1] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Liquid chromatography (LC) in direct combination with mass spectrometry (MS) has been shown to be a good analytical technique for the selective separation and detection of labile folate monoglutamates. Reversed-phase LC and electrospray-ionization MS conditions were developed and optimized for the separation and detection of 5-methyltetrahydrofolic acid, 5-formyl tetrahydrofolic acid, tetrahydrofolic acid, dihydrofolic acid and folic acid in aqueous samples. Representative and reproducible positive ion mass spectra were generated for each folate under mild MS conditions. The selective MS detection and identification of endogenous 5-methyltetrahydrofolic acid in human plasma was accomplished through the development of a straightforward C18-based solid-phase extraction procedure. This procedure allows for the qualitative assessment of 5-methyltetrahydrofolic acid in plasma. Based upon an isotope-dilution internal standard calibration study with standards, the LC-MS limit of quantitation for 5M-THF was estimated to be 0.39 ng/mnl.
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Affiliation(s)
- B C Nelson
- Analytical Chemistry Division, National Institute of Standards and Technology, Gaithersburg, MD 20899-0001, USA.
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Rubino FM. Separation methods for methotrexate, its structural analogues and metabolites. JOURNAL OF CHROMATOGRAPHY. B, BIOMEDICAL SCIENCES AND APPLICATIONS 2001; 764:217-54. [PMID: 11817030 DOI: 10.1016/s0378-4347(01)00402-9] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Methotrexate (MTX) is the prototype folate antagonist cytotoxic drug, employed in the therapy of solid tumors and leukaemias, and recently also as an immunosuppressive agent in organ transplantation, in the treatment of some autoimmune diseases and in the therapy of severe asthma. MTX is one of the very few antineoplastic drugs the therapeutic concentration monitoring of which is currently employed in clinical practice and can be routinely measured in biological samples by a number of different analytical techniques, among which are immunoenzymatic and chromatographic methods. Each technique has of course its own advantages in terms of sensitivity, specificity, speed, cost and level of expertise required. Along with therapeutic drug concentration monitoring and clinical pharmacology, fundamental research into the mechanism of action of antifolate drugs is still a field which requires the measurement of MTX, of its new analogues and of their metabolites in biological samples. This review summarizes the instrumental conditions and the performance of several published chromatographic methods employed to measure MTX, its metabolites and some analogues in clinical and biological research. More than 70 papers describing chromatographic assays for MTX and its metabolites have been published in the literature between 1975 and 2000. A wide array of experimental conditions for sample preparation, analyte separation and detection have been employed. According to their chemical properties, MTX, its metabolites and analogue drugs present in several biological samples (plasma, serum, saliva, urine, cerebrospinal fluid, tissue specimens) can be extracted, separated and detected under a variety of chromatographic conditions, i.e. on different stationary phases, under a wide choice of mobile phase conditions (acidic or neutral, employing ion-pair or micellar chromatography), followed by several detection techniques (UV-Vis spectrophotometry, pre- or post-column oxidation and fluorimetry, electrochemistry, mass spectrometry). Optimized methods allow simultaneous measurement within a few minutes of the plasma levels of MTX and its main metabolites at concentrations in the low-nM range. One special field which needs sensitive, fast and inexpensive methods for the detection and measurement of MTX is the monitoring of contamination in workplace environments, such as pharmaceutical industries and oncological hospital pharmacies, and in sewage waters. The measurement of the intracellular gamma-oligo-glutamate metabolites of biological folates, of MTX and of some analogue drugs is of great importance in basic pharmacological research. The existence of empirical quantitative relationships between the retention of individual oligomers under different chromatographic conditions and the number of added glutamic acid units allows identification of the metabolites even when authentic standards are not available.
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Affiliation(s)
- F M Rubino
- Department of Medicine, Surgery and Odontology, University of Milano at Ospedale S. Paolo, Milan, Italy.
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Pawlosky RJ, Flanagan VP, Pfeiffer CM. Determination of 5-methyltetrahydrofolic acid in human serum by stable-isotope dilution high-performance liquid chromatography-mass spectrometry. Anal Biochem 2001; 298:299-305. [PMID: 11700986 DOI: 10.1006/abio.2001.5394] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The need for specific and sensitive methods for the determination of distinct serum folates is of high priority in clinical research settings. A stable-isotope liquid chromatography-mass spectrometry (LC/ESI-MS) assay was developed for the quantitative determination of the monoglutamyl form of 5-methyltetrahydrofolic acid (5-MTHFA) in human serum. Serum samples (0.5 ml) were amended with the internal standard, [5-13C5]MTHFA that had been labeled on the glutamic acid portion of the molecule and allowed to equilibrate. The analyte was trapped onto a solid-phase cartridge and then eluted with the HPLC mobile phase. Forty microliters was taken for LC/ESI-MS analysis using electrospray ionization operated in the positive ion mode. Using the standard method of addition of 5-MTHFA to serum, a linear dilution curve (y = 12.777x - 1.404; range 0.94-97 ng x ml(-1)) was constructed. The precision of the method was 5.3% (CV) based on the analysis of four sample replicates. The mass spectrum produced upon collision induced dissociation of the analyte in serum was used to confirm the identity of the 5-MTHFA. The method was applied to the analysis of a set of serum samples that contained standardized concentrations of 5-MTHFA. The determinations of 5-MTHFA in these samples using the LC/ESI-MS procedure were found to be in good agreement with other folate methods. A highly accurate and specific method for the analysis of 5-MTHFA in serum has been developed utilizing stable isotope dilution mass spectrometry.
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Affiliation(s)
- R J Pawlosky
- Food Composition Laboratory Beltsville Human Nutrition Research Center, USDA, Beltsville, Maryland 20705, USA.
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Current literature in mass spectrometry. JOURNAL OF MASS SPECTROMETRY : JMS 2000; 35:1474-1485. [PMID: 11180639 DOI: 10.1002/1096-9888(200012)35:12<1474::aid-jms985>3.0.co;2-u] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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